Morquio syndrome

Definition

Morquio syndrome is an inherited disease of metabolism in which the body is missing or doesn't have enough of a substance needed to break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides).

The syndrome belongs to a group of diseases called mucopolysaccharidoses (MPS). Specifically, it is known as MPS IV.

Alternative Names

Causes, incidence, and risk factors

Morquio syndrome is an autosomal recessive trait. That means both your parents must pass you the defective gene in order for you to get this disease.

There are two forms of Morquio syndrome: Type A and Type B.

Persons with Type A do not have a substance (enzyme) called galactosamine-6-sulfatase.

Persons with Type B do not produce enough of an enzyme called beta-galactosidase.

The body needs these enzymes to break down a long strand of sugar molecules called the keratan sulfate sugar chain. In both types, abnormally large amounts of glycosaminoglycans build up in the body and brain, which can damage organs.

The syndrome is estimated to occur in 1 of every 200,000 births. Symptoms usually start between ages 1 and 3. A family history of the syndrome raises one's risk for the condition.

Support Groups

Expectations (prognosis)

Cognitive (thinking) function is usually normal in patients with Morquio syndrome.

Bone problems can lead to significant complications. For example, the small bones at the top of the neck may slip and damage the spinal cord, causing paralysis. Surgery to correct such problems should be done if possible.

Complications

Walking problems related to abnormal curvature of the spine and other bone problems

Calling your health care provider

Call your health care provider if symptoms of Morquio syndrome occur.

Prevention

Genetic counseling is recommended for prospective parents with a family history of Morquio syndrome. Counseling is also recommended for families who have a child with Morquio syndrome, to help them understand the condition and possible treatments.